Order N9051B Option A2B to receive a user-installed software license, which causes any existing N9051A licenses to be recognized as N9051B licenses. The N9051B-2FP license is required, while all others are optional and independent of each other.

Most of the E4980A functions are compatible with the 4284A's. Since some enhancements and updates of functionality are incorporated in the E4980A, there are primary differences summarized in the table.